1. Field
The present application relates generally to the operation and design of electronic circuits, and more particularly, to the operation and design of analog front ends.
2. Background
A conventional multi-band front end uses one power amplifier and a matching network. Mode switches are used to select between multiple signal paths to enable one of the multiple bands. Insertion loss from the mode switches contributes to degradation of the overall efficiency of the front end. Therefore, it is desirable to eliminate this insertion loss.
Some front ends utilize combination chips that provide multiple power amplifiers where each power amplifier drives signals in a selected band. The amplifier outputs share a common RF input/output (RFIO) terminal that couples the amplifier outputs to an antenna. Managing the loading effect of one path on the other paths is a major challenge.
Accordingly, a novel front end parallel resonant switch is disclosed that allows switching between multiple power amplifier outputs while controlling the loading effects of one transmit path on other transmit paths.